Yamaha YZ250F(E), Owner'S Service Manual

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ENGINE SPECIFICATIONS
2-3
Cylinder head
Volume 12.07–12.87 cm
3
(0.74–0.79 cu.in)
Warpage limit 0.05 mm (0.0020 in)
Camshaft
Drive system Chain drive (left)
Camshaft cap inside diameter 22.000–22.021 mm (0.8661–0.8670 in)
Camshaft journal diameter 21.959–21.972 mm (0.8645–0.8650 in)
Camshaft-journal-to-camshaft-cap clearance 0.028–0.062 mm (0.0011–0.0024 in)
Camshaft lobe dimensions
Intake A 31.730–31.830 mm (1.2492–1.2531 in)
Limit 31.630 mm (1.2453 in)
Intake B 22.450–22.550 mm (0.8839–0.8878 in)
Limit 22.350 mm (0.8799 in)
Exhaust A 33.370–33.470 mm (1.3138–1.3177 in)
Limit 33.270 mm (1.3098 in)
Exhaust B 25.211–25.311 mm (0.9926–0.9965 in)
Limit 25.111 mm (0.9886 in)
Camshaft runout limit 0.030 mm (0.0012 in)
Timing chain
Tensioning system Automatic
Valve, valve seat, valve guide
Valve clearance (cold)
Intake 0.12–0.19 mm (0.0047–0.0075 in)
Exhaust 0.17–0.24 mm (0.0067–0.0094 in)
Valve dimensions
Valve head diameter A (intake) 30.90–31.10 mm (1.2165–1.2244 in)
Valve head diameter A (exhaust) 24.90–25.10 mm (0.9803–0.9882 in)
Valve face width B (intake) 1.697 mm (0.0668 in)
Valve face width B (exhaust) 1.909 mm (0.0752 in)
A
B
A
B